About 30% of Adult type granulosa cell tumors of the ovary (AGCTs) are diagnosed in fertile age. In stage I, conservative surgery (fertility-sparing surgery, FSS), either unilateral salpingo-oophorectomy (USO) or cystectomy are possible options. The aim of this study is to compare oncological outcomes of FSS and radical surgery (RS) in apparently stage I AGCTs treated within the MITO group (Multicenter Italian Trials in Ovarian cancer).

Survival curves were calculated using the Kaplan-Meier method and compared with log-rank test. The role of clinicopathological variables as prognostic factors for survival was assessed using Cox's regression.

Two-hundred and twenty-nine patients were included; 32.6% received FSS, 67.4% RS. In the FSS group, 62.8% underwent USO, 16.7% cystectomy, 20.5% cystectomy followed by USO. After a median follow up of 84 months, median DFS was significantly worse in the FSS-group (10 yr DFS 50% vs 74%, in FSS and RS group, p = 0.006). No significant difference was detected between RS and USO (10 yr DFS 75% vs 70%, p = 0.5).Cystectomy-group showed a significantly worse DFS compared to USO (10 yr DFS 16% vs 70%, p < 0.001). Patients receiving cystectomy and subsequent USO showed a better prognosis, even though significantly worse compared to USO (10 yr DFS 41% vs 70%, p = 0.05). Between FSS and RS, no difference in OS was detected. At multivariate analysis, FIGO stage IC and cystectomy retained significant predictive value for worse survival.

This study supports the oncological safety of FSS in stage I AGCTs, provided that cystectomy is avoided; USO should be the preferred approach.